Pacing instruments can be used to treat patients suffering from various heart conditions that result in a reduced ability of the heart to deliver sufficient amounts of blood to a patient's body. These heart conditions may lead to rapid, irregular, and/or inefficient heart contractions. To help alleviate some of these conditions, various devices (e.g., pacemakers, defibrillators, etc.) have been implanted in a patient's body. Such devices may monitor and provide electrical stimulation to the heart to help the heart operate in a more normal, efficient and/or safe manner. In some cases, a patient may have multiple implanted devices.
Motion detectors have been used in some pacemakers and other implantable devices to obtain a measure of the activity level of the patient. For example, rate adaptive cardiac pacemakers may adjust the rate at which the patient's heart is paced up or down in response to detected motion of the patient. By so doing, the pacemaker is able to adapt to the activity level of the patient, allowing a more active lifestyle than could be achieved without rate adaptive pacing. New and alternative approaches to the use of motion sensors are desired.